Study On Performance Of Cold Recyling About Old Asphalt Pavement Mixture With Emulsified Asphalt

The construction of highway of our country during the annual maintenance engineering will produce a lot of old asphalt pavement materials,these old asphalt pavement material most discarded,waste of resources and environmental pollution caused by.Emulsified asphalt cold recycling technology can make maximum use of the old asphalt pavement material and regeneration after mixed material with good performance,low energy consumption,small pollution,emission reduction effect obvious,in line with China's strategy of sustainable development of green and low carbon development concept.Therefore the cold regeneration of old asphalt pavement material utilization technology in-depth study has important practical significance.Based on Chongqing Zhongxian's S412 pavement overhaul engineering.After summarized regeneration technology status,on the basis of the progress in the study,through a large number of laboratory tests,on different rap content and the amount of different cement emulsified asphalt cold recycling mixture performance were more in-depth study and comparative analysis,the main research contents and results are as follows:(1)By doing extraction test for RAP,the performance of old asphalt and mixtures were detected.Compared with the new aggregates,the result showed that RAP in the old asphalt has been seriously aging,but RAP can be used as a black set of material is recycled.(2)By selecting 40%,60%,80%,100% four different dosage of emulsified asphalt,cold recycled mixture are studied to maintain four regeneration mixture of synthetic gradation,the use of soil compaction test to determine their optimal fluid content;using a compaction 100 times compaction method to make Marshall test piece splitting test.Selecting the splitting strength and splitting strength ratio as the indexes to determine the optimum emulsified asphalt content index.The experimental results show that R-40: R-60 and R-100 emulsion asphalt dosage were 4.3%,4.2%,4.0% and 3.5% respectively,the additional water dosages are 3.4% and 3.3%,3.1%,3.4% respectively.(3)After finishing dosages of cement emulsified asphalt cold recycled mixture splitting test,rutting test,bending test at low temperature,Marshall test,freeze thaw split test and SEM test,comparative analysis of emulsified asphalt cold recycled mixture of mechanical properties,high temperature performance,low temperature performance,water stability performance.The results show that rap can improve emulsified asphalt cold recycled mixture of low temperature anti cracking performance of cement can significantly improve the resistance to deformation of cold recycled mixture,high temperature rutting resistance and water damage resistance ability.(4)Based on the research of the axle load conversion method with deflection and tension stress,the paper obtains the conversion method of axle load as the following layer,and introduces the structure design procedure of the cold recycling layer according to the physical engineering.(5)Through normal test of asphalt mixture in the mixing station,the results show the good performance of cold recycled mixture.In this dissertation,the results indicate that cold recycling emulsified asphalt mixture with the best ratio of rap content was 80%,2.0% cement,emulsified asphalt 4.0% water 3.1%,can be used for asphalt pavement below the surface and research results will be scientific significance for the design and construction.